Mathematical Modeling of Infrared Assisted Hot Air Drying of Ginger Slices

Abstract

Infra-red assisted hot air drying studies were conducted on ginger slices of diameter 20 plus or minus 2.5 mm and thickness 5 plus or minus 0.5 mm. Drying experiments were executed under infra-red and hot air temperature of 60°C with two levels of air velocities: 0.8 metre per second and 1.4 metre per second. The drying rate was found to increase proportionately with the drying air velocity, thereby minimising the total drying time. Time taken for drying ginger slices from an initial moisture content of 442 per cent to a final moisture content of 8.4 per cent at 0.8 metre per second air velocity was 300 min. Whereas, it took 210 min to lower the moisture content of ginger from 433.33 per cent to 6.67% under the drying air velocity of 1.4 metre per second. Infrared drying temperature of 60°C in combination with air velocity of 0.8 metre per second showed better results for quality evaluation with reduced drying times. Logarithmic model fitted the experimental data well for the whole range of temperatures.